title: Differentiating pacemaker-mediated tachycardia from tachycardia due to atrial tracking: utility of V-A-A-V versus V-A-V response after postventricular atrial refractory period extension.
abstract: BACKGROUND
  Dual-chamber pacemaker systems can lead to two forms of pacemaker-facilitated tachycardia: pacemaker-mediated tachycardia (PMT) and tracking of sinus or atrial tachycardia. Current pacemaker algorithms cannot always differentiate between these two tachycardias.
  
  
  OBJECTIVE
  The purpose of this study was to investigate a novel algorithm for distinguishing the two mechanisms of pacemaker-facilitated tachycardia, which is based on the specific termination response to postventricular atrial refractory period (PVARP) extension.
  
  
  METHODS
  We prospectively tested our algorithm using the Medtronic Virtual Interactive patient (VIP) II simulator (version 1.53) and a Medtronic Adapta ADDR01 dual-chamber pacemaker.
  
  
  RESULTS
  Thirty-five scenarios that triggered "PMT detection" by the device were evaluated. All 12 scenarios of atrial tachycardias with intact AV conduction terminated with a Vp-Ar-Vs (V-A-V) response as a result of PVARP extension. Of the 11 scenarios of atrial tachycardia with complete heart block, all terminated with a Vp-Ar-As-Vp response. All four episodes of PMT with intact AV conduction terminated with a Vp-Ar-As-Vs (V-A-A-Vs) response. Of the eight episodes of PMT with complete heart block, all terminated with a Vp-Ar-As-Vp response.
  
  
  CONCLUSIONS
  In the presence of intact AV conduction, the V-A-V response to PVARP extension is specific to atrial (or sinus) tachycardia, whereas the V-A-A-Vs response is specific to PMT. Recognizing the difference between the two forms of pacemaker-facilitated tachycardias has important implications for pacemaker programming.
authors.affiliation: Department of Medicine, Division of Cardiology, Cornell University Medical Center, New York, New York, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Ip
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Liu
authors.forename: Jim W
authors.initials: JW
authors.lastname: Cheung
authors.forename: George
authors.initials: G
authors.lastname: Thomas
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Lerman
mesh_terms: D000465:Algorithms; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D013610:Tachycardia / Q000503:physiopathology*